Certainty Defined: An Industry Glossary

At Schebler, we pride ourselves in bringing certainty to your chimneys and exhaust systems, with unmatched quality and service. That’s why, in order to remove any lingering uncertainty you may have regarding industry terms and abbreviations, we’ve created this comprehensive glossary as a simple and convenient reference for you.

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Glossary

A

AHJ

Stands for Authority Having Jurisdiction. Refers to a governmental organization or designated individual with legal responsibility for building codes, standards and inspection.

Air Quality Standards

The level of pollutants prescribed by law or regulation that cannot be exceeded during a specified time in a defined area.

AL 29-4C^®

Super ferritic stainless steel designed and produced by Allegheny Ludlum used in Schebler’s UL 1738 listed chimneys for venting condensing systems.

Aluminized Steel

Steel on which an aluminum coating is applied to resist corrosion.

Ambient Temperature

The temperature at a point or area expressed as an average of the surrounding areas or materials. Ambient temperature is generally given to be 70-80°F (21-27°C); an average of daily and seasonal variation.

Approved

Acceptable to the code official or other authority having jurisdiction.

ASHRAE

American Society of Heating, Refrigerating and Air Conditioning Engineers. Schebler Chimney Systems is a member.

ASME

The American Society of Mechanical Engineers. Schebler certification: ASME code for pressure vessel fabrication and repair.

Atmospheric Appliance

An appliance that requires a natural draft for venting. Venting is under negative pressure.

B

B-Vent

A double-walled metal chimney/flue. Contains an aluminum inner liner and galvanized outer shell. Rated to 550 D. Nonpositive pressure rated.

Barometric Damper

A balanced air damper that allows outside air into the vent system to equalize the draft.

Barometric Pressure

Atmospheric pressure as determined by a barometer.

Blower

A fan used to force air under pressure.

Boiler

A closed vessel in which water or other fluid is heated. The heated or vaporized fluid exits the boiler for use in various processes or heating.

Boiler Efficiency

Difference between the energy input and energy output in a boiler.

Boiler Horsepower

The measure of a boiler’s capacity to produce steam.

Breeching

The horizontal portion of a chimney system or grease duct from the boiler, hot water heater, generator, dishwasher or kitchen appliance hood to the vertical portion of the system.

BTU

Abbreviation for British thermal unit, which is the quantity of heat required to raise the temperature of 1 lb. (454 g) of water 1°F (0.56°C) (1 BTU = 1055 J).

Building Heating Appliance

A fuel-burning or electric boiler operating at a gauge pressure not over 50 psi.

Burner

A burner introduces the mixture of fuel and air into an appliance at the desired rate per the specific appliance requirements.

C

Category I Appliance

An appliance that operates with a nonpositive vent static pressure and with a vent gas temperature that avoids excessive condensate production in the vent.

Category II Appliance

An appliance that operates with a nonpositive vent static pressure and with a gas vent temperature that can cause excessive condensate production in the vent.

Category III Appliance

An appliance that operates with a positive vent static pressure and with a vent gas temperature that avoids excessive condensate production in the vent.

Category IV Appliance

An appliance that operates with a positive vent static pressure and with a vent gas temperature that can cause excessive condensate production in the vent.

Chimney

A primarily vertical structure containing one or more flues to carry gaseous products of combustion and air from an appliance to the outside atmosphere.

Chimney (Factory-Built)

A listed and labeled chimney composed of factory-made components assembled in the field per the manufacturer’s instructions and the listing conditions.

Chimney (Masonry)

A field-constructed chimney composed of solid masonry units, bricks, stones or concrete.

Chimney (Metal)

A field-constructed chimney of metal.

Clearance to Combustibles

The distance required per UL listing between the single wall liner or outer shell of the double wall products to combustible material such as a shaft, roof, etc.

Clean Out

A spot in the chimney system or grease duct where inspection or cleaning of the system can be made. Done with a 90T or 90Y or inline access door.

Continuous Weld

A metal joining method that produces a product without visible interruption or variation in quality.

Code

Regulations and subsequent amendments to any emergency rule or regulation that the administrative authority having jurisdiction has lawfully adopted.

Code Official

The officer or other designated authority charged with the administration and enforcement of this code, or a duly authorized representative.

Condensate

The liquid that separates from gas, including flue gas, due to a reduction in temperature.

Corrosion

The decay of metal due to chemical reaction. Schebler’s continuous seam welding minimize chimney corrosion (see Solutions > Corrosion Resistant).

cUL

Stands for Canadian Underwriters Laboratory. Schebler products carry specific certifications indicating satisfaction of safety standards set by Canadian Underwriters Laboratories. Also indicated by ULC (Underwriters Laboratory of Canada).

D

Damper

A manually or automatically controlled device to regulate draft or the rate of flow of air/combustion gases.

Draft

The pressure difference existing between the appliance or any component part and the atmosphere that causes a continuous flow of air and products of combustion through the gas passages of the appliance to the atmosphere.

Draft (Mechanical or Induced)

The pressure difference created by the action of a fan, blower or ejector that is located between the appliance and the chimney or vent termination.

Draft (Natural)

The pressure difference created by a vent or chimney because of its height, and the temperature difference between the flue gases and the atmosphere.

Dew Point

The temperature at which condensation starts.

Direct-Vent Appliances

Appliances that are constructed and installed so that all air for combustion is derived.

Double Wall

A chimney that’s constructed of an inner liner and outer shell, reducing the conduction of heat to the outside. This allows the chimney to be installed without combustion danger to support materials.

Draft

The rising gas creates a pressure difference called draft, which draws combustion air into the appliance and expels the exhaust gas outside through the chimney.

Draft Hood

Located at the top of an atmospheric appliance where the breeching or chimney connects. The draft hood helps bring outside air into the vent to help draft.

E

Efficiency

The ratio of the input of energy to the output of energy.

Engine Generator

A device that converts mechanical energy into electrical energy with its engine.

Engineered Stack

A chimney that is engineered to be self-supporting or free-standing. Schebler’s engineered stack expertise includes sizing, design, engineering, fabrication and installation (see Engineered Stacks).

eVent^® Series

Prefabricated chimney system for high-efficiency condensing boilers. Available in odd and even sizes from 5″ to 48″. UL 1738-Listed, corrosion-resistant, AL 29-4C or 316L stainless steel products. (See Prefabricated Chimneys for links to all eVent models).

F

Fire Resistance Rating

The time, in minutes or hours, that materials or assemblies have withstood a fire exposure as established per the test procedures of NFPA 251.

Field Fabricated

Non-UL fabrication such as grease ducts, flues, breeching or chimney products.

Flange Connection

A ½” rolled lip on Schebler products that allow secure connection of products. Schebler’s flange connection increases pressure rating and eliminates condensate leakage.

Flanged Boiler Connection

Boiler outlet that has a rolled lip and requires a flanged boiler kit.

Flue

A passage for products of combustion – hot air, gas, steam or smoke; chimney.

Flue Gases

Products of combustion plus excess air in appliance flues or heat exchangers.

Flue Liner (Lining)

A system or material used to form the inside surface of a flue in a chimney or vent, to protect the surrounding structure from the effects of combustion products and for conveying combustion products without leakage to the atmosphere.

Fuel Gas

Natural gas, manufactured gas, liquefied petroleum gas or mixtures of these gases.

Forced Draft

Air under positive pressure produced by fans at the point where air or gases enter a unit, such as a combustion furnace.

FyreGuard™

Double wall UL 1978-listed and UL 2221 Classified grease duct product, zero-clearance to combustibles and two-hour fire rating. This eliminates the need for a fire-rated chase and secondary insulation.

G

Grease Ducts

A containment system for the transportation of air and grease vapors that is designed and installed to reduce the possibility of the accumulation of combustible condensation and the occurrence of damage if a fire occurs within the system.

Generator

A device that converts mechanical energy into electrical energy.

Guy Section

A bracing attachment for tall chimney structures that protects from wind displacement. Should be used when the chimney extends beyond the vertical limits above the roof line. The guy section should be connected to guy wires or a rigid guy structure.

H

Heavy Wall Fabrication

An integral part of Schebler-engineered stack production, featuring certified welders with expertise in a variety of high-integrity metals.

I

IMC

International Mechanical Code. Establishes minimum regulations for mechanical systems using prescriptive and performance-related provisions.

Induced Draft Fan

A fan located inside a system that assists in the exhaust of flue gas.

Insulation

Ceramic fiber material of various thicknesses is used in Schebler chimney systems to enable tight installations by reducing clearance to combustibles; lower building cooling loads; and to diminish heat loss in low-temperature environments.

ISO

International Organization for Standardization. Schebler’s ISO 9001:2000 certification indicates fulfillment of worldwide quality management requirements.

L

Labeled

Equipment, materials or products to which have been affixed a label, seal, symbol or other identifying mark of a nationally recognized testing laboratory, inspection agency or other organization concerned with product evaluation. They also maintain periodic inspections of the production of the above-labeled items and whose labeling indicates either that the equipment, material or product meets identified standards or has been tested and found suitable for a specified purpose.

Listed

Equipment, materials, products or services are included in a list published by an organization acceptable to the code official. These organizations maintain high standards in the production and evaluation of products and services and conduct periodic inspections/evaluations to ensure compliance. When a product or service is listed, it has been tested and found to meet an identified standard or is suitable for a specific purpose.

M

Material (Combustible)

Any material that will burn regardless of its auto-ignition temperature.

Material (Noncombustible)

A substance that will not ignite and burn when subjected to a fire.

Makeup Air

Outside air introduced into the mechanical room to help draft.

Modulating

The action of a control from its maximum to minimum position in either predetermined steps or increments of movement as caused by its actuating medium.

N

NFPA

National Fire Protection Association – an International Codes and Standards Organization.

NFPA 37

The standard for the installation and use of stationary combustion engines and gas turbines.

NFPA 96

Standards for ventilation control and fire protection of commercial cooking operations.

NFPA-211

Standards for chimneys, fireplaces, vents and solid fuel burning appliances.

O

Obround

A space-conserving chimney shape consisting of two semicircles connected by parallel straight sides.

P

Pressure Drop

The loss in pressure due to friction or obstruction in pipes, valves, fittings, regulators and burners.

Pressure Test

An operation performed to verify the gas-tight integrity of gas piping following its installation or modification.

Pressure Relief Valve

A pressure-actuated valve held closed by a spring or other means and designed to relieve pressure automatically over the device’s setting.

R

Rain Test

UL test indicating that an unsatisfactory amount of water does not enter the rain cap of a chimney.

S

Sequence Draft Control™

Schebler’s design service which offers boiler manufacturers and building owners a complete engineered venting system that maintains consistent stack pressure for hot water or steam appliances within manufacturer requirements. This system automatically compensates for all operating conditions ensuring proper appliance operation with common vented systems.

Shaft

An enclosed space extending through one or more stories of a building, connecting vertical openings in successive floors, or floors and the roof.

Skin Temperature Rise Tests

UL study subjecting a chimney to a series of burn tests at temperatures up to 1800° F. Determines safe clearances from the chimney outer shell to combustible materials.

SlimVent™

The industry’s only double wall UL 1978-listed and UL 2221-classified grease duct product that is designed as a safer alternative to field fabricated non-UL-listed grease ducts. SlimVent is designed for low overhead clearances where no round grease duct will fit.

Special Gas Vent

Vents intended for use with listed Category II, III, and IV appliances, and are investigated per the Standard for Safety for Venting Systems for Categories II, III and IV Gas-Burning Appliances, UL 1738.

Stainless Steel

Material with different levels of corrosiveness used as the liner in UL-listed chimneys and grease ducts.

Structural Tests

UL study indicating support plates and wall supports have been physically tested to carry a load four times that allowed by the UL listing.

T

Thermal Expansion

Alteration to the temperature inside a chimney or grease duct system that causes the metal surfaces to expand.

Tool-Less End Cap

UL-listed end cap used on grease duct that doesn’t require tools to remove, making inspection and cleaning easier at clean-out locations.

U

UL

Underwriters Laboratories. Schebler Chimney Systems products carry specific certifications indicating satisfaction of safety standards set by Underwriters Laboratories. cUL and ULC refer to Canadian requirements.

UL 103

Safety standard for prefabricated chimneys intended for venting gas, liquid and solid-fuel-fired residential-type appliances and building heating appliances.

UL 1738

Safety standard for venting systems intended for gas-burning appliances, Categories II, III and IV.

UL 1978

The standard for grease ducts and their clearance to combustibles.

UL 2221

Indicates a zero-clearance to combustibles for fire-resistive grease ducts.

Vee Band

A stainless-steel V-shaped band that draws the flanges together on two pieces of chimney products, securing them together.

V

Vent

A pipe or other conduit composed of factory-made components, containing a passageway for conveying combustion products and air to the atmosphere, listed and labeled for use with a specific type or class of appliance.

Vent (Special Gas)

A vent listed and labeled for use with listed Category II, III and IV appliances.

Vent (Type B)

A vent listed and labeled for use with appliances with draft hoods and other Category I appliances that are listed for use with Type B vents.

Vent (Type BW)

A vent listed and labeled for use with wall furnaces.

Vent (Type L)

A vent listed and labeled for use with appliances that are listed for use with Type L or Type B vents.

Vent Gases

Products of combustion from appliances plus excess air and dilution air in the vent connector, gas vent or chimney above the draft hood or draft regulator.

Venting System

A continuous open passageway from the flue collar or draft hood of an appliance to the outside atmosphere to remove flue or vent gases. A venting system is usually composed of a vent or a chimney and a vent connector, which if used, assembles to form the open passageway.

Venting System (Forced Draft)

A portion of a venting system using a fan or other mechanical means to cause the removal of flue or vent gases under positive static vent pressure.

Venting System (Induced Draft)

A portion of a venting system using a fan or other mechanical means to remove flue or vent gases under nonpositive static vent pressure.

Venting System (Mechanical Draft)

A venting system designed to remove flue or vent gases by mechanical means, consisting of an induced draft portion under nonpositive static pressure or a forced draft portion under positive static pressure.

Venting System (Natural Draft)

A venting system designed to remove flue or vent gases under nonpositive static vent pressure entirely by natural draft.

W

Water Column

The amount of gas pressure necessary to displace a column of water a specified number of inches. 28 inches of water column equals 1 psi.

Wind Load Tests

UL test indicating load equivalents of 110-mph winds have been applied to the chimney with acceptable results.

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